Optimizing Biochar Use for Soil Carbon Sequestration and Crop Yield Based on Soil pH

A new study in Applied Biological Chemistry examines how biochar application rates affect soil carbon storage and crop yields under different soil pH conditions. Researchers tested pepper residue biochar on Chinese cabbage fields in South Korea, comparing acidic soil (pH 5.8) and near-neutral soil (pH 6.8). Results show that optimal biochar rates depend heavily on initial soil chemistry, not just application volume. In acidic soil, soil organic carbon stock rose steadily with biochar rate, reaching 36.8 t C per hectare at the highest application. Crop yield peaked at 300 kg per 10 ares. In near-neutral soil, carbon gains leveled off above 300 kg per 10 ares, and yield topped out earlier at 200 kg per 10 ares. The study recommends 200 to 300 kg per 10 ares as a balanced range for both productivity and carbon sequestration. This research highlights that blanket biochar recommendations miss important site-specific factors. For carbon project developers and farmers, matching biochar rates to soil pH could improve both crop outcomes and carbon credit yields. The findings support more precise agricultural carbon management rather than one-size-fits-all approaches.